Trichomonas vaginalis is a protozoan sexually transmitted disease (STD), which causes vaginitis and urethritis. Complications associated with this infection include preterm birth and HIV acquisition. Despite the availability of generally effective single dose, affordable antibiotic therapy, this infection remains extremely prevalent worldwide. At a time when bacterial STDs such as gonorrhea and chlamydia have decreased, rates of trichomoniasis have remained constant. Contributors to this continued infection rate may include less sensitive diagnostic tests, especially in males, lack of systematic partner notification and treatment methods, and possibly, decreased susceptibility to metronidazole. In fact, the most effective means of partner notification for STDs in general has not been well studied. We propose to investigate three different methods of partner notification for trichomoniasis via a randomized study design (including partner referral, partner delivered medication and medication delivered by a field worker), determining relative effectiveness rates based on recurrent infection in the female. The role of stigma as a barrier to partner notification and treatment will also be evaluated. The information gained from this study will have broad applicability for control of other STDs such as gonorrhea and chlamydia. In addition, we will utilize specimens from the study to improve diagnostic methods for T. vaginalis, to examine strain differences using PFGE, and to examine the prevalence of resistance strains and their potential contribution to treatment failure.